/Engine/Plugins/Experimental/ScreenReader/Source/ScreenReader/Public/GenericPlatform/ScreenReaderUser.h
Immediately stops speaking any currently spoken announcement. Does nothing if there is no announcement currently being spoken.
FScreenReader::Handled() if the request to stop speaking is successfully processed. Else returnsFScreenReaderReply::Unhandled()
[FScreenReaderReply](API\Plugins\ScreenReader\GenericPlatform\FScreenReaderReply) StopSpeaking()